Attack on the uncastled king: bishop to g3 (f2·6)
c9-28501naming tag (square·N)Opens in the app if installed, otherwise downloads the APK.
The tactical motive
Chess960 twist: use the unusual starting setup of the pieces.
Uncastled king: the enemy king is stuck in the centre — punish it before it castles.
Winning tactic: there is a move that gains a decisive advantage — find it.
Difficulty 1610 ShuffleRating — for advanced tacticians.
White to move — find the best continuation
How to recognize this tactic
In Chess960 the pieces start on unfamiliar squares, so tactics appear earlier and from unusual angles. Do not trust classical patterns — read the actual lines of the bishops, the rooks and the queen from where they really stand in this position.
An uncastled king in the centre is a standing target. Look for ways to open the central files and diagonals against it with checks and threats before it can shelter — every tempo the king spends in the middle is a chance for a combination.
This position hides a concrete tactic that wins material or mates. Start with the most forcing candidate moves — checks, captures and threats — and calculate each to a clear end before choosing; the winning line is usually the one the opponent cannot meet.
General method: before you move, list the forcing candidates — every check, every capture, every direct threat — and calculate those first. The solution to a tactic is almost always among them.
Position on the board
White: king g1, queen c1, rook b1 f1, bishop c2 f2, knight h1 e3, pawn b2 d2 e2 g2 h2 a4 f5.
Black: king e8, queen d6, rook a8 f8, bishop b3 c7, knight d8 h8, pawn a5 c6 f6 g6 d7 e7 h7.
15 white and 15 black pieces are on the board; the puzzle position arises after move 14.
The position in numbers
Material is level — 38 points of pieces on each side (pawn = 1, knight and bishop = 3, rook = 5, queen = 9).
The white king stands on g1, the black king on e8.
It is White to move on move 14, with 24 legal replies to weigh — only the line that keeps the advantage solves the puzzle.
White keeps 7 pawns, Black 7. No file is fully open, so the heavy pieces have to be pried in. Half-open for White: c.
The White king has 0 empty squares to step to right now — the fewer they are, the closer a mating net.
Solution & explanation
Main line
14. Bg3 Qb4 15. Bxc7
Why it works
- Great move! bishop to g3 keeps the pressure (+5.2).
- Well found: bishop to c7 (+5.1).
- You win a piece — the bishop.
- If instead Qb4, then Bxc7 and you win the bishop.
Move by move
- 14. Bg3 — bishop to g3
- Qb4 — queen to b4
- 15. Bxc7 — bishop to c7 (capture)
Types in this puzzle
Skewer
A line attack forces the valuable piece to move, exposing the one behind it.
A skewer is a pin turned inside out: the valuable piece stands in front and something cheaper hides behind it. The big piece must step aside, and you collect the one that was sheltering in its shadow. Scan for the enemy king or queen sharing a file, rank or diagonal with another enemy piece. The deadliest version comes with check — the king moves, the rook behind it dies.
Mate defense
Mate is threatened — parry it and stay on top.
Mate defense: your opponent is one move from mating you — but it is your turn, and that changes everything. Find the defense that kills the mating threat while keeping your advantage: often a check or a counter-threat that leaves no time for the mate. First name the exact square where the mate would land — otherwise you are defending blind. The mistake is playing a "defensive" move that does not actually remove the threat.
Uncastled king
The king lingered in the middle — punish the delay.
Punishing the uncastled king: your opponent delayed castling, and now his king is stuck on its starting square under fire. In Chess960 this is deadlier than in classical chess — the king may start in the center or near the edge, and the familiar defensive setups simply do not apply. The signs: the victim still holds castling rights, and the files toward his king are half-open. Open lines before the king manages to hide.
About this position
These pieces come from starting position #604.
SP-604 · ThroneScout — A knight starts on the edge (a/h) and the king sits centrally on d or e; the mirror twin stays in this family too.
The king starts on e1, the rooks on a1 and f1, the queen on c1.
The kingside rook already stands on f1, so castling short moves only the king, from e1 to g1.
The bishops stand on b1 and g1; their long diagonals reach h7 and a7 once the c- and f-pawns step aside.
One second-rank pawn starts with no defender at all: g2.
The setup belongs to the ThroneScout family; read right to left it becomes position 268.
The engine's main line opens with f4.
Morozov Balance Index: 0 of 100 — class D — largest edge. Engine evaluation of the starting position: +81 centipawns for White (depth 45, 400 000 000 nodes).
In 50 self-play games White scored 63.0% (95% CI 49.1–75.0%).
Explore position #604Provenance
Mined from the project's engine self-play games.
Pack 012 · SP-604
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